92 Accord - Gear Lights on Dashboard

The following ONLY occurs during wet weather: I have a 92 Honda Accord LX with automatic transmission. Starting from a stop, the car feels as though it's trying to start in third
gear. Once we get going, I cannot seem to get it to go beyond third gear. On the highway, I can't go past 50 mph, and the tachometer stays around 3. I noticed that with the engine running and while at a stop, if I shift into other gears, the D4 light on the dashboard remains lit (i.e., if I shift to reverse, the R light and D4 light are lit). The car moves in the correct direction while in the other gears, but the D4 light stays on.
I think the Transmission Control Module (TCM) is bad, but I wanted to get others' opinions. Is there a way I can test if the TCM is bad? Do you have any other ideas of the problem?
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Rachel wrote:

Interesting. That points to damp wiring.

More symptoms of defective wiring.

You must determine if the TCM thinks it has a problem. Find the module and watch the lamp in the window. Note the number of flashes, if any, when you turn the ignition on. On my old Prelude the module is under the carpet where a passenger's left foot would rest. Pull back the carpet to see the indicator.
It's likely that the TCM is sensing some moisture-related problem under the hood. The number of lamp flashes indicates the location.
--
Chuck



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I had almost exactly the same problem (91 Accord), except the gear indicator showed the selected gear, and my 'S' light was on. (Actually, the 'S' light would wink out sometimes, and the car would drive normally. Then, it would come on, and the transmission would go into 3rd gear.) It seemed to be related to wet weather.
Here are some links that may help - or not :) http://www.hondacarforum.com/honda-3/16786-flashing-s-light-91-accord-lx.html http://www.honda-tech.com/zerothread?id –2851&postid3094332 (old, some pictures gone)
After reading some advice on the Internet, I came to the conclusion that the TCU was bad. Some of the literature suggested it was worth a try to fix the board itself. So I removed the TCU and exposed the board. Sure enough, there was a bad capacitor, as evidenced by some obvious leakage onto the circuit board. I bought a replacement at Radio Shack for $1.50, unsoldered the old capacitor, cleaned the board as best I could, and soldered the new replacement in. That did the trick, and that repair has held for about 5 months now.
If you feel adventuresome, I suggest you remove the TCU and look at the circuit board. If you find an obviously bad component, try replacing it. (Leaky capacitors are one thing - you can still see the specs on the side; burnt resistors may totally obscure what they were, as you cannot see the colored bands.) Chances are, you have not much to lose, since a rebuilt TCU will probably cost about $150.00.
-- R Flowers
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On Wed, 23 Apr 2008 21:28:34 -0500, "R Flowers"

On the other hand, I bought an ECU at a junkyard for something like $40. It's been working fine for at least two years.
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:)http://www.hondacarforum.com/honda-3/16786-flashing-s-light-91-accord...http://www.honda-tech.com/zerothread?id –2851&postid3094332(old, some
Dear R Flowers,
Your reply is so helpful since you experience similar symptoms as what I have described. Last night, I removed the TCM and stared at the board for quite some time. I could not see anything noticeably damaged. I went ahead and ordered a rebuild TCM, and I plan to install it tonight. Would you happen to have an idea why these symptoms occur during wet weather? The area around the TCM and the TCM itself were dry. Thanks again for everyone's help!
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Rachel wrote:

Moisture is unlikely to affect the control module. The circuit board is covered in a sealant to block the effects of humidity. What code was the board flashing, if any?
I've revived TCMs by replacing the electrolytic capacitors at a cost of just a few dollars. The tantalum and polystyrene capacitors are unlikely to deteriorate. Note that the electrolytic capacitors used are 105 degree C versions.
--
Chuck



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Worth a look anyway, I guess. Hope you will be on the road tomorrow!
-- R Flowers
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Thank you to everyone who replied with advice! As an update, I replaced the TCM, and the car is running smoothly - in wet and dry weather!
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Thank you to everyone who replied with advice! As an update, I replaced the TCM, and the car has been running smoothly - in wet and dry weather!
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